<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>filter筛选数组元素</title>
</head>

<body>
  <script>
    // ============================== filter 筛选数组元素 ==============================
    const arr = [10, 20, 30, 40]

    // 需求：筛选出 >= 30 的数据



    
    // 改写成箭头函数
  </script>
</body>

</html>